常涉及的类型转换包括：数值与字符串的转换、对象与字符串的转换、数组与字符串的转换等。
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>JavaScript 类型转换</title>
</head>
<body>
<script>
var num = 123.55;
var isJS = true;
var names = ["iOS", "Android"];
var person = {"name":"devZhang", "job":"iOS dev"};
var date = new Date();
var numToStr = num.toString();
document.write("<br>数值转字符串：" + numToStr + "<br>");
var strToNum = Number(numToStr);
document.write("<br>字符串转数值：" + strToNum + "<br>");
var boolToStr = isJS.toString();
document.write("<br>布尔值转字符串：" + boolToStr + "<br>");
var strToBool = Boolean(boolToStr);
document.write("<br>字符串转布尔值：" + strToBool + "<br>");
var arrToStr = names.toString();
document.write("<br>数组转字符串：" + arrToStr + "<br>");
var strToArr = arrToStr.split(",");
document.write("<br>字符串转数组：" + strToArr + "<br>");
var objToStr = JSON.stringify(person);
document.write("<br>对象转字符串：" + objToStr + "<br>");
var strToObj = JSON.parse(objToStr);
document.write("<br>字符串转对象：" + strToObj + "<br>");
</script>
</body>
</html>
数值转字符串：123.55
字符串转数值：123.55
布尔值转字符串：true
字符串转布尔值：true
数组转字符串：iOS,Android
字符串转数组：iOS,Android
对象转字符串：{"name":"devZhang","job":"iOS dev"}
字符串转对象：[object Object]